SNVS497F November   2008  – September 2016 LM27341 , LM27341-Q1 , LM27342 , LM27342-Q1

PRODUCTION DATA.  

  1. 1 Features
  2. 2  Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Boost Function
      2. 7.3.2 Low Input Voltage Considerations
      3. 7.3.3 High Output Voltage Considerations
      4. 7.3.4 Frequency Synchronization
      5. 7.3.5 Current Limit
      6. 7.3.6 Frequency Foldback
      7. 7.3.7 Output Overvoltage Protection
      8. 7.3.8 Undervoltage Lockout
      9. 7.3.9 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Enable Pin and Shutdown Mode
      2. 7.4.2 Soft-Start Mode
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1  Inductor Selection
        1. 8.1.1.1 Inductor Calculation Example
      2. 8.1.2  Inductor Material Selection
      3. 8.1.3  Input Capacitor
      4. 8.1.4  Output Capacitor
      5. 8.1.5  Catch Diode
      6. 8.1.6  Boost Diode (Optional)
      7. 8.1.7  Boost Capacitor
      8. 8.1.8  Output Voltage
      9. 8.1.9  Feedforward Capacitor (Optional)
      10. 8.1.10 Calculating Efficiency and Junction Temperature
        1. 8.1.10.1 Schottky Diode Conduction Losses
        2. 8.1.10.2 Inductor Conduction Losses
        3. 8.1.10.3 MOSFET Conduction Losses
        4. 8.1.10.4 MOSFET Switching Losses
        5. 8.1.10.5 IC Quiescent Losses
        6. 8.1.10.6 MOSFET Driver Losses
        7. 8.1.10.7 Total Power Losses
        8. 8.1.10.8 Efficiency Calculation Example
        9. 8.1.10.9 Calculating Junction Temperature
          1. 8.1.10.9.1 Conduction
          2. 8.1.10.9.2 Convection
          3. 8.1.10.9.3 Method 1
          4. 8.1.10.9.4 Method 2
            1. 8.1.10.9.4.1 Method 2 Example
          5. 8.1.10.9.5 Method 3
            1. 8.1.10.9.5.1 Method 3 Example
    2. 8.2 Typical Applications
      1. 8.2.1 LM2734x Configuration From VIN = 7 V to 16 V, VOUT = 5 V For Full Load at 2 MHz
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
        3. 8.2.1.3 Application Curves
      2. 8.2.2 LM2734x Configuration From VIN = 7 V to 16 V, VOUT = 5 V For Full Load at 1 MHz
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
        3. 8.2.2.3 Application Curves
      3. 8.2.3 LM2734x Configuration From VIN = 5 V to 16 V, VOUT = 3.3 V For Full Load at 2 MHz
        1. 8.2.3.1 Design Requirements
        2. 8.2.3.2 Detailed Design Procedure
        3. 8.2.3.3 Application Curves
      4. 8.2.4 LM2734x Configuration From VIN = 5 V to 16 V, VOUT = 3.3 V For Full Load at 2 MHz With SYNC = GND
        1. 8.2.4.1 Design Requirements
        2. 8.2.4.2 Detailed Design Procedure
        3. 8.2.4.3 Application Curves
      5. 8.2.5 LM2734x Configuration From VIN = 5 V to 16 V, VOUT = 3.3 V For Full Load at 2 MHz With SYNC = 1 MHz
        1. 8.2.5.1 Design Requirements
        2. 8.2.5.2 Detailed Design Procedure
        3. 8.2.5.3 Application Curves
      6. 8.2.6 LM2734x Configuration From VIN = 3.3 V to 16 V, VOUT = 1.8 V For Full Load at 2 MHz With SYNC = 1 GND
        1. 8.2.6.1 Design Requirements
        2. 8.2.6.2 Detailed Design Procedure
        3. 8.2.6.3 Application Curves
      7. 8.2.7 LM2734x Configuration From VIN = 3.3 V to 16 V, VOUT = 1.8 V For Full Load at 2 MHz With SYNC = 1 MHz
        1. 8.2.7.1 Design Requirements
        2. 8.2.7.2 Detailed Design Procedure
        3. 8.2.7.3 Application Curves
      8. 8.2.8 LM2734x Configuration From VIN = 3.3 V to 9 V, VOUT = 1.2 V For Full Load at 2 MHz With SYNC = 2 MHz
        1. 8.2.8.1 Design Requirements
        2. 8.2.8.2 Detailed Design Procedure
        3. 8.2.8.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 Compact Layout
      2. 10.1.2 Ground Plane and Shape Routing
      3. 10.1.3 FB Loop
      4. 10.1.4 PCB Summary
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Related Links
    4. 11.4 Receiving Notification of Documentation Updates
    5. 11.5 Community Resources
    6. 11.6 Trademarks
    7. 11.7 Electrostatic Discharge Caution
    8. 11.8 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

5 Pin Configuration and Functions

DSC Package
10-Pin WSON
Top View
DGQ Package
10-Pin MSOP-PowerPAD
Top View

Pin Functions

PIN TYPE(1) DESCRIPTION
NO. NAME
1, 2 SW O Output switch. Connects to the inductor, catch diode, and bootstrap capacitor.
3 BOOST I Boost voltage that drives the internal NMOS control switch. A bootstrap capacitor is connected between the BOOST and SW pins.
4 EN I Enable control input. Logic high enables operation. Do not allow this pin to float or be greater than VIN + 0.3 V.
5 SYNC I Frequency synchronization input. Drive this pin with an external clock or pulse train. Ground it to use the internal clock.
6 FB I Feedback pin. Connect FB to the external resistor divider to set output voltage.
7 GND G Signal and power ground pin. Place the bottom resistor of the feedback network as close as possible to this pin for accurate regulation.
8 AVIN I Supply voltage for the control circuitry.
9, 10 PVIN I Supply voltage for output power stage. Connect a bypass capacitor to this pin.
DAP DAP G Signal or power ground and thermal connection. Tie this directly to GND (pin 7).
See Application Information regarding optimum thermal layout.
(1) G = Ground, I = Input, O = Output